“It’s not very many, when 10,000 use the port every day,” said policy director Rod McKenzie. “But the intention is a good one, which is that if you’re going to plan for a Brexit no deal, how are you going to manage a massive traffic jam leading to the port of Dover?

“Doing it is not a bad thing, but we think it should have been done about a year ago and been continually stress-tested after that to see what the various problems would be.

“This is too little, too late. It looks like window dressing.”

A Department for Transport spokesperson said each driver was paid £550 to take part.

'Enormous pressure'

Dover MP Charlie Elphicke was also critical of the exercise, writing on Twitter that a different route using Kent’s motorways could work better.

Routing lorries via Manston is not the answer. Far better to extend the tried and tested traffic management system on the A20 at Dover to Kent’s motorways. That way lorries can be effectively managed, got most speedily to the ports and all our motorways can be kept open 1/ https://t.co/vWS4OC4AVb

Mr McKenzie added that the road network around Manston Airport was “certainly not adequate” for the potential volume of traffic that could come as a result of a no deal Brexit.

“Clearly the lorries have to stack up somewhere, we don’t want motorways turned into lorry parks,” he said.

“Manston Airport is basically a runway which they’ve turned into a lorry park for this emergency, but the whole road system leading to Dover will be under enormous pressure if there is a no deal Brexit and long lorry queues… if there are stops at customs.”

He added that hauliers could have a headache with travel permits too. “If it’s a no deal, we’re in real difficulty,” he said.

“At the moment you travel the continent with no checks and no stops, you just roll on and roll off those ferries. We lose that in March, and that would mean we’ll have to apply for permits. There are only 2,000 permits, there are 40,000 lorries that need those permits.”

“Surely that system will change, you can’t just go, ‘38,000 lorries can’t go to Europe?’ That’s madness!” said Graham.

Mr McKenzie replied: “There’d be no one happier than me if the rules got changed”.